In recent years, attention has been driven to semiconductor devices provided with light-detecting sensors (also referred to as photosensors) (see Patent Document 1).
Semiconductor devices provided with photosensors include CCD image sensors, CMOS image sensors, and the like. Such image sensors are used, for example, in electronic apparatuses like digital still cameras or cellular phones. Further, as semiconductor devices including photosensors in their display portions, touch panels and the like have been developed.
In a semiconductor device including a photosensor, light emitted from an object to be detected or external light reflected by the object to be detected is detected directly by the photosensor or condensed by an optical lens or the like and then detected.